6. Chemical Quantities & Aqueous Reactions
Complete Ionic Equations
1PRACTICE PROBLEM
A redox titration of 150.0 mL of 0.110 M CrSO4 with 0.110 M KMnO4 was performed at 25 °C with its pH being maintained at 2.50 using a suitable buffer. One half of an electrochemical cell is made up of the solution in contact with a platinum electrode. The other half-cell is a standard hydrogen electrode. The two half-cells are joined by a wire and a salt bridge, and the cell potential is measured with a voltmeter to track the titration's progress. If the expected products are Cr3+ and Mn2+, what is the net ionic equation for the titration reaction?
A redox titration of 150.0 mL of 0.110 M CrSO4 with 0.110 M KMnO4 was performed at 25 °C with its pH being maintained at 2.50 using a suitable buffer. One half of an electrochemical cell is made up of the solution in contact with a platinum electrode. The other half-cell is a standard hydrogen electrode. The two half-cells are joined by a wire and a salt bridge, and the cell potential is measured with a voltmeter to track the titration's progress. If the expected products are Cr3+ and Mn2+, what is the net ionic equation for the titration reaction?
ANSWERS OPTIONS
A
MnO4−(aq) + H+(aq) + Cr2+(aq) → Cr3+(aq) + Mn2+(aq) + H2O(l)
B
MnO4−(aq) + 5 Cr2+(aq) → 5 Cr3+(aq) + Mn2+(aq)
C
MnO4−(aq) + 8 H+(aq) + 5 Cr2+(aq) → 5 Cr3+(aq) + Mn2+(aq) + 4 H2O(l)
D
MnO4−(aq) + 4 H2O(l) + 5 Cr3+(aq) → 5 Cr2+(aq) + Mn2+(aq) + 8 H+(aq)